The present invention relates to devices for applying compressive pressures against a patient's limb.
Blood flow in a patient's extremities, particularly the legs, markedly decreases during extended periods of confinement. Such pooling or stasis is particularly acute in surgery and during recovery periods immediately thereafter.
Blood flow compressive devices, such as shown in U.S. Pat. Nos. 4,013,069 and 4,030,488, incorporated herein by reference, develop and facilitate the application of compressive pressures against the patient's limb and in so doing promoting venous return. The devices comprise a pair of sleeves which are wrapped around the patient's limbs, with a controller for supplying the pressurized fluid to the sleeve.
These sleeve devices may be seen in U.S. Pat. Nos. 4,402,312 and 4,320,746, which are also incorporated herein by reference.
One use for the above mentioned sleeves is the prevention of deep venous thrombosis (DVT) which sometimes occurs in surgical patients who are confined to bed. When a DVT occurs, the valves that are located within the veins of the leg can be damaged which in turn can cause stasis and high pressure in the veins of the lower leg. Patients who have this condition often have leg swelling (edema) and tissue breakdown (venous stasis ulcer) in the lower leg.
It has been shown that pneumatic compression can be highly effective in the treatment of such edema and venous ulcers. However, it is desirable to improve operation of the devices.